Figure 8-3. Same Link Using Cdm-750 And Doubletalk Carrier-In-Carrier - Comtech EF Data CDM-750 Installation And Operation Manual

CDM-750 High Speed Trunking Modem
DoubleTalk Carrier-in-Carrier Option

Figure 8-3. Same Link Using CDM-750 and DoubleTalk Carrier-in-Carrier

Carrier 1
Traditional Full Duplex Link
The CDM-750 CnC module operates on the near-zero signal before the demodulator, and is
waveform agnostic. This means that no prior knowledge of the underlying modulation, FEC, or
any other waveform specific parameter is required in order to perform the signal cancellation
operation. The only caveat to this is that the waveform must be sufficiently random.
CDM-750 CnC operates from 1 to 63 Msps. Interference will compromise CnC links just as they do
non-CnC links. Acquisition of the demodulator is improved by minimizing the delay search range;
Carrier 2
Duplex Link with DoubleTalk Carrier-in-Carrier
Figure 8-4. Duplex Link Optimization
8–6
Revision 1
MN-CDM750
Composite
Carrier 1
Carrier 2